A novel infrared thermography technique for measuring heat transfer in transonic turbine blades

Thesis

This thesis presents a new measurement methodology aimed at accelerating progress in the Aviation industry while ensuring reliable results. A novel measurement system employing Infrared (IR) Thermography was developed for the Oxford Turbine Research Facility (OTRF), a national engine-representative high-pressure turbine test facility operating with rotational speed of 300 m s−1 and transonic flow.

The literature review evidences that there is still considerable work to do to thoroughly understand the applicability of IR thermography to fast moving targets, and particularly to accurately quantify and minimise the sources of error. The work in this dissertation sought to fill this gap by conceiving accurate and novel calibration and processing methods. The methodology and design requirements, described in the thesis, were used and validated in the OTRF.

The infrared data of blades captured in the OTRF and processed to full surface heat transfer quantities were validated against thin-film gauges experimental data and CFD simulation, in both instances a good agreement was found, proving that the methodology surpassed standard point-based measurement techniques, and demonstrating a step change in heat transfer measurements. Scalable Nusselt number on the rotor blade, not previously possible with thin-film gauges, was achieved using the developed IR thermography methodology. Finally, the results proved the need to carefully select the camera integration time to balance image quality and accuracy.

Authors: Sisti, M

• DOI: 10.5287/ora-vyaqkoneg
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English